Mode-selective noncontact excitation of microcantilevers and microcantilever arrays in air using the ultrasound radiation force

Abstract

We demonstrate the use of focused ultrasound waves to excite eigenmodes of microfabricated structures such as atomic force microscopy microcantilevers and coupled microcantilever arrays, among the smallest objects that have been excited in air using ultrasound radiation force. The method is based on the radiation force produced by a double-sideband suppressed carrier ultrasound waveform, centered at 500 kHz. The difference frequency between the sidebands, ranging from 10 to 200 kHz, excited resonances of these structures. Frequency response curves and deflection shapes were consistent with conventional base excitation, demonstrating the feasibility of noncontact excitation for a variety of microscale devices.